I think you’re asking about free electron flow through a metal conductor which is way more complicated than you might like.

It’s worth learning about atomic orbitals, which are basically probability distributions around an atomic nucleus where electrons can be found in various conditions. There are many different patterns of these distributions, which represent different energy states possible for the atom, and their complexity increases in larger atoms. Here’s hydrogen:

Sometimes an electron transitions from a higher energy orbital to a lower one. Total energy is conserved, so the exact difference in energy levels between the orbitals is emitted as a photon of light. That photon has a very specific color (frequency) based on the difference in the energy levels of the transition. This is how neon signs work, with energy absorbed by the neon gas atoms and then very quickly emitted again as photons at the characteristic frequency.

That idea leads into quantum energy levels, spectral lines of various materials, spectroscopy, and beyond, even into astronomy with Doppler shifts of spectra indicating our relative velocity to a given star. But I’m getting off track.

A solid metal is mostly a 3 dimensional crystalline lattice of metal ions and a collection of delocalized electrons that can freely flow throughout the lattice. Another way to think of it is a lattice of atoms that collectively have an enormous shared valance electron orbital throughout which free electrons can move without transitioning energy states (but that freedom to move is what makes them delocalized).

Note that each atom/ion only contributes one electron to the free pool. For example, Copper has 29 protons, which means it needs 29 electrons to be neutrally charged. In a copper metal lattice, each ion will still have 28 electrons bound up in its lower orbitals, and they won’t be participating in any electrical current flow through the metal.

This chemistry chapter attempts to explain that, and then goes on to give some very specific answers about the speed of electrons moving through your DC circuit.

electrons actually loop around in a closed DC circuit in the speed of light

On average, electrons "move forward" much much slower than that:

https://en.wikipedia.org/wiki/Drift_velocity

But even the whole "electrical signal" is slower than the speed of light:

https://en.wikipedia.org/wiki/Velocity_factor#Typical_velocity_factors

could we tag and track an individual electron as it flows

no. this is what Heisenberg's uncertainty principle is about. we cannot know both a quantum particle's location and it's velocity with high accuracy at the same time. if we know with high accuracy how fast it's moving, we can only have a very vague guess of where it is, or vice versa

I guess I want to know this in order to understand whether electrons actually loop around in a closed DC circuit in the speed of light or are they just pushing the electron in front of them, creating a domino effect, not actually traveling very far?

In a wire, it's the second one. The energy moves at the speed of light. (nearly) The electrons make their way around the circuit much more slowly.

Short answer: yes.

I think it depends on how you measure.

See also: wave-particle duality.

They are usually very particle like.

The extreme is semiconductors and band fuckery. There you have a lot of stuff that only makes sense with electron particles jumping around accelerating and colliding. You can talk about mean free path in conductors etc.

They do however interact a lot via their charge, so electricity propagating is usually a pressure wave mostly visible in the electric field, with electrons only doing very little, moving slowly. This field is however driven by the electrons, so it really is electrons doing that.

Resistance, diodes, even heat conduction (/"resistance" to heat transfer) directly follows from electrons as particles interacting with atoms or themselves.

I think you loose these particle effects in (type 1) superconductivity. Your cooper pairs are so smooth and non-interacting they might aswell be clouds if you don't zoom in enough (quantum circuits sometimes have singular amounts of those charge carriers running in circles in a tiny superconductor loop).
However, when you look into why superconductivity is a thing and at what temperature you see it etc., that once again derives directly from the properties of electrons and the layout of your material.

Or maybe you meam do electrons have dimensions and physical properties? That they don't.
They have a charge, speed, momentum, ... but interaction is via the charge. That is what touching means, there is no further collision (technically there is electroweak force stuff).
They are not points either because qm eave blurriness stuff.

For your specific electron movement questions. I think electrons in metals under normal current where the metal heats only a litte move at snails pace, literally. In semiconductors it's a lot faster, about bullet speeds if you push some current. Metals could probably also get to bullet speeds but they would vaporize and explode due to the electric and magnetic fields. Faster than that isn't really feasible. Btw. the random motion at room temperature is also at that scale, though due to quantum effects it's not a bouncing around.

So when you have circuits operate near light speed, that is an electron pressure wave not electrons. The electrons react via quantum fuckery, but changing between speeds and positions at the slow pace described. The reaction is carried on via the electric field. The speed of electricity is the speed of interaction between electrons, not the speed of electrons.

Without the electrons reacting and causing their own electric field changes, the electric field still carries the effects but it quickly dilutes. This is called radio (depending on the timescale of your change), and while it does transmit electricity it does so very weakly, nothing compared to the "continuously electron reinforced short range interaction" wire.

are they merely negative charge with no physical form?

Charge is a property of a particle. You can't have charge with no physical form.

Whether electrons zoom or bump or flow depends on how closely you look. The best answer, without several courses of physics, is just don't worry about it, you apply charge to a wire and it conducts. The short "real" answer is that electrons kind of move like a gas along the conductor.

Veritasium - Energy doesn't flow in wires
https://www.youtube.com/watch?v=bHIhgxav9LY

Veritasium - How electricity actually works
https://www.youtube.com/watch?v=oI_X2cMHNe0

Veritasium - Making the blue LED (for the n-type, p-type demos of electron flow)
https://www.youtube.com/watch?v=AF8d72mA41M

Mass of electron, (early fundamental experiments)
https://en.wikipedia.org/wiki/Electron_mass